Pressure fluid motor



ll I7 Sept. 19, 1944.

F. E. SINCLAIR PRESSURE FLUID MOTOR Filed July 23, 1940 Ewen/for:

z'nclaz'n $3 A... A-mw I (my.

Patented Sept. 19, 1944 PRES sum: MOTOR Frank E. Sinclair, Glaremont, N. H., assignor'to Sullivan'Machinery Compan a' corporation of Massachusetts Application July 23, 1340,. Serial No. 346,939

7 Claims.

This invention relates to pressure fluid motors,

and more particularly to improvements in the fluid distributionmeans of a pressure fluid motor of the reciprocating piston type An object of this invention is to provide an improved pressure fluid motor- Another object is to provide an improved fluid distribution means for a pressure fluid motor wherein improved distributing valve means is employed for controlling.

the flow of pressure fluid. to the motor cylinder.

A further objectis to provide an improved fluid distributing valve for a pressure fluid. motor, having improved means for throwing the valve into its different operating positions. Still another object is to provide an improved fluid distributing valve mechanism having improved throwing means whereby the distributing valve is thrown a substantial interval prior to the opening of the cylinder exhaust. A still further object is to. provide an improved pressure fluid: motor of the longstroke, reciprocating piston type, having 1111-- vertical sectional J viewv through a pressure fluidi motor constructed in. accordance with the illustrative embodiment of the invention:

Fig. 2 is a sectional view similar to Fig.1; showing the distributing valve and motor piston in different positions.

Fig. 3'is an'enlarged end elevational' viewi-ofthei improved fluid distributingv valve;

In this illustrative embodiment of the inven-- tion there is shown a pressure fluid motor of the reciprocating piston type especially designed for use: in impact tools, such as pavement breakers. Itwill be evident, however, that features of the invention may be embodied. in pressure fluid motors of various other types.v

The pressure fluid motor disclosed hereincomprises a motor cylinder I having an elongated bore 2 containing areciprocatory hammer piston 3. The motor cylinder hasafront head 4 having; an axial bore 5 in which. atappet 6 is mounted? for reciprocatory movement. This tappet projectswithinthe forward: end of the. cylinder bore inthe manner shown, ina position to: receive the impact blows of the motor piston and to transmit such blows to the shank I of a working implement, such as a conventional pick point or the. like. The motor cylinder has a rear head plate 8, and interposed between the head plate anda rear head block 9 is a valve block I0. The head" block S-has a bore II, and the head plate, valveblock and the rearward portion of the motor cylinder are fitted within the head block bore in the manner shown. The front head 4 and the rear head block llmay be secured to the motor cylinder in any suitable manner.

Now referring to the improved fluid distributing means, it willbe noted that formed within the head plate 8- and-valve block I0 is a valve chamber l2 in which a distributing valve 13- of the flanged sleeve type is reciprocably mounted. The head plate and the valve block have alined uniform bores l4 and [-5 respectively, and the valve has a cylindric sleevelike body l6slidingly fitted. within these bores. Formed externally on the valve body midway between its ends is an annular flange ll adapted to seat at its opposite faces against plane seating. surfaces l8 and I9 onthe head plate and valve block respectively. The valve flange I1 is arranged within an annular recess 20 provided by end bores 2| and 22 in the headplate and valve block respectively and an annuular space between the head plate and valve-block. Pressure fluid may be supplied. to theannular recess 20 from any suitable source through. a passage 23 communicating with a chamber 24 formed in the rear head block 9, and through aseries of passages 25 connecting the chamber 24 with the annular recess 26. Communicating with the bores 2| and 22 at the opposite sides of the external valve flange l! are annular grooves 26 and. 21 respectively. The

sleevelike valve body l fi'has transverse partitions 28' spaced from its ends to provide end recesses 29, and the valve is made hollow at 30 between thesepartitions for the purpose of lightness. For further. lightening the valve, the opposite faces of the external valve flange I! are annularly recessed at 3|. Fluid. distribution passages 32 communicate with the groove 2'! at the rear face oflthe external valveflange H,- and' ports 33 connectf these passages with the: forward end of the cylinder bore. A series of fluid distribution passages 34 connect. the groove 26- atthe forward face of the external. valveflange with the rear end of the cylinder bore. The motor cylinder is passage 39 communicating with the rear end of the bore l through a port 4|. sages 42 and 43 connect the annular supply recess with the passages 38 and 39 respectively; The cross sectional areas of the restricted leak passages 42 and 43 are such that the flow of fluid therethrough to the passages 38 and 39 respectively is not suflicient to maintain, when the cylinder ends of passages 38 and 39 are uncovered,

a much higher pressure in the ends of the valve chamber at the opposite ends of the valve body than exists in the cylinder bore where the passages 38 and 39 communicate with the latter;

so that when the passages 38 and 39 are connected to exhaust through the endsof the cylinder bore under the control of the motor piston, a large reduction'in the pressure acting on the ends of the valve body occurs, as will later be explained. Also when the cylinder pressure falls because the rate of admission is insuflicient to maintain it at line pressure, the pressure at an end oi the valve. will be reduced when connection with the cylinder is established. The valve is guided solely at the exterior periphery of the cylindric sleevelike body Hi, and there is a slight clearance at 44 between the exterior periphery of the external valve flange TI and the walls of the bores 2| and 22, and this restricted clearance provides restricted clearance spaces 45 and 46 between the exterior of the external valve flange and the walls of the bores 20 and 2| for the purpose of meter-' ing the flow of pressure fluid from the annular supply recess 20 past the distributing valve to the ends of the cylinder bore.

The mode of operation of the improved pressure fluid motor is as follows. When the distributing valve I3 is in the position shown in Fig. 1 and pressure fluid is supplied from the passage 23 through chamber 24 and passages 25 to-the annular supply recess 20, pressure fluid may flow from the supply recess 20 through therestricted clearance space 45, through the valve chamber |2 past the forward face of the external valve flange l1 and through-groove 26 and distribution passages 34 to the rear endof the cylinder bore. The pressure fluid acting on the rear pressure area of the motor piston 3 moves the latter forwardly to effect its working stroke, i. e. to deliver an impact blow to the tappet 6. When the motor piston starts its forward movement from the position shown in Fig. 1, the forward end of the cylinder bore is connectedto exhaust andthe rear surface of the valve body and a portion of the rear face of the external flange are connected to exhaust through the passages. 39 and 32 respectively. As the motor piston moves forwardly, the leading edge of the piston first overruns the exhaust passages 35, thereby to cut off the front end of the cylinder bore and the rear valve surfaces from the exhaust. Upon continued forward piston movement, the leading edgeof the piston overruns the port 31 of the passage 39, and thereafter the following'edge of the piston uncovers the port 38 of the passage 38, thereby connecting the forward end of the bore M at the forward side Restricted pas- H I of the valve body to the rear end of thecylinder bore, and as a result, the pressure in the valve chamber at the forward side of the valve body is substantially reduced. When the port 31 of the passage 39 is covered by the motor piston, the pressure fluid leaking through the restricted passage 43 to the passage 39 flows through the port 'pression pressure is transmitted through the ports 33, distribution passages 32 and annular recess 21 to the bore 22 at the rear side of the external valve flange, and this compression pressure acts on the exposed rear pressure area of the external valve flange to supplement the pressure leaking through the passage 43, thereby to throw the valve forwardly from the position shown in Fig. 1 to the position shown in Fig. 2. The pressurefluid leaking through the passage 43 to the passage 39 and through the port 4| to the rear end of the valve chamber at the rear side of the valve body acts on the effective rear pressure area of the valve body to hold the valve in its foremost position. After the valve is thrown, the piston continues to move forwardly, and as the motor piston approaches the forward end of its stroke, its following edge uncovers the exhaust passages 35;connecting the rear end of thecylinder bore to exhaust, and the motor piston thereafter delivers its impact blow to the tappet. When the valveis in the position shown in Fig. 2, pressure fluid may flow from the/annular supply recess 20 through the restricted clearance space 46,- through the valve chamber [2 past the rear face of the external valve flange and through annular recess 21 and'distribution passages 32 and ports 33 to the forward end of the cylinder bore, the pressure fluid acting on the forward pressure area of the motor piston to move the latter 'rearwardly' to effect its return stroke. When the motor piston starts its rearward movement from the position shown in Fig. 2, the rear end of the cylinder is connected to exhaust, and the front surface of the valve body anda portion of the front face of the external flange are connected to 'exhaust'throu'gh passages 38 and 34 respectively. As the motor piston moves rearwardly, its leading edge first overruns the exhaust, passages 35and thereafter overruns the port.36 of the passage 38, and upon continued rearward piston movement the following edge of the piston uncovers the port 31. When the port 3'| is uncovered by the following edge of the piston, the rear end of the bore l5 at the rear side of the valve body is connected through port 4|,

passage 39 and port 31 with the front end of the cylinder bore, and as aresult,'the'pressure in the valve chamber at the rear sideof the valve body is substantially reduced. When the port 36 of the passage 38 is covered by the motor piston, the pressure fluid leaking throughtherestricted passage 42 to the passage :38 flows through the port 40 to the front end of the valve chamber at the front end of the valvejbody to act on the effective front pressure area 'of the valve body As the piston moves towards the rear end of the cylinder, the pressure fluid'tra'pped within the rear end of the cylinder b'ore is compressed, and this compressionpressure is transmitted through the distribution passages 34 and the groove 26 to the bore 2| at the front side. of the external val've flange'to supplement thepr'essure leaking throughthe passage 42, thereby to throwthe; valve rearwardly-from. the position shown in; Fig. 2. to the. position shown in Fig; 1. The 'pressure fluid leaking through. the. restricted passage... through the port 40 to the front end of the valve chamber at the forward side of the valve, body acts on the'forward pressure area of the valve.

body: to, hold the valve in its rearmost position. Upon continued rearward; piston movement, the following edge of the piston uncovers the exhaustpassages 35, connecting the front end of the cylinder bore to the exhaust. The operations: above described are rapidly repeated during nor-. mal running of the motor.

As a result of this invention it will be noted that an improvedpressure fluid motor is provided having improved fluid distribution means which is not only simple in design but also-extremely eflicient. It will also be. evident that by the provision of the improved valve throwing means for the valve the latter is thrown in an improved manner, resulting in a motor which is. not only efficient but is also extremely rapid andpowerful in operation. Other uses and advantages ofthe improved fluid distribution means will be clearlyapparent to those skilled'in the art.

While there is in this application specifically described one form which the invention may assume in practice, it will be understood that this form of the same is shown for purposes of illustration and that the invention may be modified and embodied in various other forms without departing from its spirit or the scope of the ap-- pended claims.

What I claim as new Letters Patent is: r r

1. In a pressure fluid motor, the: combination comprising a cylinder having a bore, a piston reciprocabletherein, a piston-controlled exhaust for said cylinder bore, means provid'ing'a valve chamber, distribution passages leading from said chamber respectively to the opposite ends of said cylinder bore, a pressure fluid supply, a fluid actuated fluid distributing valve movably mounted in said valve chamber for alternately connecting said distribution passages with said supply, relatively restricted passage means for continuously supplying live pressure fluid to equal opposed pressure areas on said valve, pressure reducing passages connected to the cylinder bore at points each spaced longitudinally of the cylinder bore a substantial distance with respect to said cylinder exhaust and controlled by said piston for alternately connecting said opposed pressure areas to the cylinder bore to effect a reduction in the pressure acting on said areas, and means for alternately subjecting other opposed pressure areas on said valve to compression pressure built up by the piston in the ends of said cylinder bore, whereby said valve is thrown during each piston stroke a substantial interval prior to the opening of the cylinder bore exhaust.

2. In a pressure fluid motor, a cylinder having a bore, a piston reciprocable therein, and fluid distribution means for supplying pressure fluid to and exhausting fluid from said cylinder bore for efiecting reciprocation of said piston including an automatic pressure fluid actuated fluid distributing valve, passage means controlled by said valve for supplying pressure fluid to the opposite ends of said cylinder bore, an exhaust port for said cylinder bore overrun by said piston, and means for throwing said valve a substantial interval prior to the opening of the cylinder exhaust durand desire to secure by ing each. piston stroke including. a pressure area. on each end of'saidvalve and relatively restricted passage means for supplying pressure fluid from. a relatively constant pressure source to each of. said pressure areas, exhau'stpassages communicating with said pressure areas and opening into. said cylinder bore at opposite sides of said ex;-,

haust port at points eachv spaced longitudinally of the cylinder bore a substantial distance. from said exhaust port, 'saidexhaust passage openings. being so located that the one nearer the end of the: cylinder bore toward which the'piston travels iscovered-by the piston before the other is uncovered, and separate pressure areas on said valve subjected to thecompression pressures within the opposite ends of said cylinder. bore, said. valve. being thrown by the pressure onone of said. first mentioned pressure areas and by the compression. pressure acting on one of said separate pressure,

areas.

3. In a pressure fluid motor, a cylinder having a bore, a piston reciprocabletherein, and fluid. distribution means for supplying pressurefluid to and exhausting fluid from said cylinder-bore for efiecting reciprocation of said piston including an automatic pressure fluid actuated fluid distribut-v ing valve, passage means controlled by said valve for supplying pressure fluid to the opposite endsof said cylinder bore, a centrally located exhaust port for said cylinderbore, and means for throwing said valve a substantial interval prior to the opening of the cylinder exhaust during each piston stroke including a pressure area on each end of said valve and means'for supplying pressure fluid at a controlled rate to eachof said pressure areas, exhaust passages communicating with said pressure areas and opening into said cylinder bore at opposite sides of said exhaust port at points each'spaced longitudinally of the cylinder bore a substantial distance from said exhaust port, said exhaust passage openings being so lo--'- cated that the one nearer the end of the cylinder bore toward which thepiston travels'is covered-'- by the piston before the other is uncovered, said exhaust passages of sufiicient cross sectional area to efiect free communication between said pressure areas and said cylinder bore, and separate pressure areas on opposite ends of said valve, one

subjected to the compression pressure Within one end of said cylinder and the other subjected to the compression pressure within the opposite end of said cylinder, said valve being thrown by pressure fluid supplied to one of said first mentioned pressure areas and by the compression pressure acting on one of said separate pressure areas.

4. In combination, in a motor, a cylinder having a bore, a piston reciprocable in said bore, an exhaust for said cylinder overrun by said piston, fluid distribution passages leading to the opposite ends of the cylinder, a pressure fluid supply, and means for connecting said pressure fluid supply alternately to the distribution passages including a valve having oppositely directed surfaces of equal area thereon each having a continuously open connection with the pressure supply, and vent passages connecting said areas. to said cylinder bore at opposite sides of said cylinder exhaust, said vent passages communicating with the cylinder bore at points spaced a substantial distance longitudinally of the cylinder bore from said cylinder exhaust, said piston cutting off communication of said vent passages with said cylinder bore simultaneously during a portion of each of its strokes whereby the pressure built up on one of said valve areas effects a'throwing of the valve as soon as onenof' said vent passages-is uncovered and at'ia substantial interval prior to the opening ofsaid cylinder exhaust.

'5. In a pressure fluid motor, the combination comprising a cylinder having a bore, a piston reciprocable' therein, a piston-controlled exhaust for said cylinder bore, means providing a valve chamber, distribution passages leading from said chamber respectively to the opposite ends of the 'cylinder bore, a pressure fluid supply, a fluid actuated fluid distributing valve movably mount! ed in said valve chamber for alternately connecting said distribution passages with said supply, said valve having a body provided with an annular flange and presenting equal opposed pressure. areas at its opposite ends, relatively restricted passages means for-continuously supplying pressure fluid to said equal opposed pressure areas on, said valve at the opposite ends of said valve body, said valve flange having opposed pressure, areas alternately subjected to compression pressure built up within'the ends of the cylinder'bore by-the piston, and pressure reduce ing passages for said equal opposed pressure areas connected to the cylinder bore at points spaced longitudinally of the cylinder bore a substantial distance from said cylinder exhaust, whereby said valve is thrown by the combined action of line pressure and compression pressure a substantial interval prior to the opening of the cylinder bore exhaust during each piston stroke.

6. In combination; in a motor, a cylinder, a piston reciprocable therein, a pistoncontrolled exhaustfor said cylinder, fluid distribution passages opening into each end of said cylinder,--a pressure fluid supply, and means for controlling the connection of said supply alternately to the distribution passages-including a valve controllingv saiddistribution passages and having an an-' nular flange intermediate its ends and end body portions at opposite sides of said flange, means for subjecting said end body portions to different pressures in diiferent positions of the motor piston including restricted passage means for delivering fluid continuously to said end body portions, said'annular valve flange having its opposite sides subjected :to compression pressure builtup in the cylinder ends by the piston, and larger vent passage means communicating with said cylinder at points spaced longitudinally thereof-a substantial distance from said cylinder exhaust and intermittently controlled by the motorrpistonfor alternately reducing the pressure on said endbody portions, whereby the valve is thrown a substantial interval prior to the opening of the cylinder exhaust during each piston stroke.

7. In combination, .in a pressure fluid motor, a cylinder, a piston reciprocable therein, a piston-controlled exhaust for said cylinder, fluid distribution passages opening into each end of said cylinder, a pressure'fluid supply, and means for controlling the connection of said fluid supply alternately'to said distribution passages includ-- ing a fluid distributing valve controlling said distribution passages and having an enlarged an-:

nularflangev intermediate its ends and opposite end body portions providing substantially equal opposed pressure areas at opposite sides of said flange, andmeans for subjecting saidopposed,

pressure areas of said end body portions to different pressures in difierent positions of said motor piston including relatively restricted passage means for; delivering fluid constantly to said opposed pressure areas and relatively larger vent passage means communicating with the cylinder at points spaced longitudinally thereof a substantial distance from said cylinder :exhaust and in termittently controlled by said motor piston for reducing the pressure on said pressure areas of said end body portions, whereby said valve is thrown a substantial interval prior to the opening of said cylinder exhaust during each piston stroke. v

- FRANK E. SINCLAIR. 

